Rotary take-up for sewing machines



Aug. 17, 1954 R. L. HOFFMEISTER 5 1 ROTARY TAKE-'IUP FOR SEWING MACHINES 5 Filed Feb. 14, 1951 5 Sheets-Sheet 1 INVENTOB Faberf oawoffmeisfer WITNESS BX gw M AT TOENEY Aug. 17, 1954 R. HOFFMEISTER 2,686,485

ROTARY TAKE-UP FOR SEWING MACHINES Filed Feb. 14, 1951 5 Sheets-Sheet 2 INVENTOB Faberz O6. woffmeisier WITNESS. I B

' ATTORNEY Aug. 17, 1954 R. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES 5 Sheets-Sheet 3 Filed Feb. 14,- 1951 INVENTOB Pollen aflwoffmeisier A T TOENEY WITNESS.

Aug. 17, 1954 Filed Feb. 14, 1951 R. L. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES Palm 0C WITNESS M BY W w a u 46 j 4% sets-Sheet 4 INVENTOB Woffineisfer AT TOENE' Y Aug. 17, 1954 R. L. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES 5 Sheets-Sheet 5 Filed Feb. 14, 1951 INVENTOE Poberf ofiwoffmeisfer WITNESS ATTORNEY Patented Aug. 17, 1954 UNITED STATES PATENT OFFICE ROTARY TAKE-UP FOR SEWING MACHINES Application February 14, 1951, Serial No. 210,957

13 Claims. 1

This invention relates to a needle-thread takeup for sewing machines, and more particularly to a rotary type take-up in which a pair of rotary elements having fixed axes of rotation are utilized to satisfy the thread handling requirements of high speed, lock-stitch sewing.

It is one feature of the present invention to provide a double rotary take-up comprising a plurality of rotary take-up elements which are arranged to operate upon the needle-thread in a manner such that during the stitch-setting cycle their combined frictional drag action upon the thread will result in no substantial increase or decrease in the tension imposed upon the thread by the conventional tension device.

I-he use of a heavy check spring and a heavy tension setting in combination with a double rotary take-up is made possible by that type of take-up which operates to counter the regular tension device at specific intervals in the stitchforining cycle. Such a take-up is disclosed in my oo-pen'ding application entitled Rotary Take- Up for Sewing Machines, Serial No. 41,472, dated July 30, 1948, now Patent No. 1554,14 1, dated May 22, 1951. This co-pending application discloses a double rotar take-up device comprising rotary thread-engaging pins which rotate in a common direction which is the same as the lead of the thread. By rotating the pins in the direction of thread lead a secondary tensioning effect is built up which acts against the regular tension device to assist the take-up in pulling the required amount of thread through the tension device at the stitch-setting point, and it simultaneously acts to relieve some of the tension on the thread limb leading from the take-up: to the work, the latter function tending to preclude the possibility of puckering of the Work due to overtensioning of the thread. Due to the fact that the rotation of the take-up pins in the direction of the lead of the thread tends partially to nullify the effect of the tension device itself, it then becomes clear that such a machine may operate properly with a heavier tension setting than that employed in conventional rotary take-up devices. Thus, in' the device disclosed in my co-pend-ing application a relatively heavy check spring may be employed.

However, for certain classes of work, and particularly those involving light or cheap thread, this latter type of take-up also has its disadvantages, experience has shown'that the heavy tension setting tends to cause the thread to break.

Thus, the primary object of the present iii-" 2 vention is to provide a double rotary take-up device which may be operated effectively with a moderately heavy tension device so as to provide a machine which will have most of the advantages of prior machines having av light thread-tension as well as those of that machine which is disclosed in my co-pending application.

A still further feature of the invention is the provision of a rotary take-up device which is designed in a manner such that abnormal winding of the thread about the take-up pins whenever the thread breaks is precluded.

A still another feature of the present invention is the provision of a double-disk rotary take up device which is so designed that it will occupy a minimum of space in the head portion of the machine.

A preferred embodiment of the invention i1 lustrating the above,- as Well as other features, is described in the ensuing specification referring to the accompanying drawings in which Fig. 1 is a front elevation partly in longitudinal vertical section of a single needle lock-stitch sewing machine incorporating the new take-up.

Fig. 2 is a head end elevation of the sewing machine showing the orientation and direction of rotation of the take-up disks.

Fig. 3 is a sectional view taken substantially along the line 3-3 of Fig. 1.

Fig. 4 is a sectional View taken substantially along the line 4'4 of Fig. 2.

Fig. 5 isa sectional view taken substantially along the line 55 of Fig. 1.

Figs. 6 to 10- are fragmentary face views of the machine showing the positions of the take-up ele-" nients during the complete stitch-forming cycle.

Fig. 11 is a fragmentary head end elevation of the sewing machine illustrating a modified form of the invention which includes an anti-winding device.

Fig. 12 is a sectional view taken substantially along the line l2l2 of Fig. 11.

The sewing machine embodying the present invention, comprises a conventional frame in cluding a bedportion I upon which is seated an upright standard 2 which in turn carries a horizontal hollow bracket-arm 3. Rotatably jour naled inthe bracket-arm 3 is an arm' shaft 4 which is actuated by a belt-driven balance wheel 5. The arm shaft i reciprocates a needle-bar 6 by means of a crank i and connecting link 8'. An eye-pointed needle 9 is secured to the lower end' of the needle-bar 6. Mounted adjacent the needle bar for longitudinalmovement is a presser-bar it having a presser foot ll fixed to its lower end. The arm-shaft 3 also drives a VET- tically disposed rotary shaft 12 through a pair of bevel-gears 13. The vertical shaft 62 in turn drives a rotary-hook shaft 14 horizontally disposed within the bed portion l of the sewing machine; the driving connection between the two shafts comprising a pair of bevel gears [5. A rotary-hook I6 is secured to the end of the hook-shaft It and is driven in a two to one speed ratio relative to the arm shaft 4.

A feed advance eccentric l1 and a feed lift ec. centric I8 are also carried by the arm-shaft t. Surrounding the respective eccentrics are vertically disposed pitman links [8 and 25 which oscillate rock shafts 2| and 22 within the bed of the sewing machine. Rock-arms 23 and 24 are respectively secured to the rock-shafts 2i and 22, and impart the usual four-motion feeding movements to a feed-bar 25 to which is aflixed a feeddog 26.

The needle-thread take-up mechanism includes a pair of parallel rotary shafts 2'! and 23 journaled in the head of the arm 3, the shaft 21 being driven from the main shaft 4 by means of gears 23 and 30. These latter two gears are so designed that the shaft 2'! is driven at twice the speed of the shaft 4. The shaft 28 is driven by the shaft 21 through the medium of a pair of gears 3i and 32 which are designed in a fashion such that the shaft 23 will be driven in synchronism with the main shaft 4. Thus, the shafts 21 and 28 will be driven counterclockwise and clockwise, respectively, as viewed in Figs. 3 and 5.

A disk 33 is aifixed to the end of the shaft 21 while a disk 34 is afiixed to the shaft 28, and from the above it will be understood that the disk 34 is driven in synchronism with the main shaft 4, while the disk 33 is driven at twice the speed of the main shaft and in the opposite direction. The disk 33 has affixed thereto a single thread-engaging pin 35 which projects outwardly therefrom while the disk 34 carries a single pin 36 which projects inwardly therefrom. Referring particularly to Figs. 1 and 4, it will be observed that the present takeup comprises a double rotary disk unit in which the two overlapping disks 33 and 34 are spaced apart axially to form therebetween a thread compartment into which project the thread-controlling pins 35 and 36 from the opposing disk faces. Referring to Figs. 1, 2 and 4, a face-plate 59, secured to the machine head by screws 51, is provided with apertures 52 and 53 for receiving respectively the shaft hub 32 and the rotary disk 33. The outer face of this faceplate 59 affords at its upper portion a stationary wall which, together with the disk as forms a coplanar extension of the thread compartment between the disks 33 and 34.

The take-up is threaded by passing a thread 31 from a supply source through stationary guides 38 and 38' to a conventional tension device 39, over a check spring d3 adapted to yield in a counterclockwise direction about the tension device, under a stationary guide or pin 4! and then upwardly and about the thread-engaging pins 35 and 36 and the hub 32 of the disk 34. From the thread-controlling elements 35, 33 and 42, the thread runs downwardly to a thread guid 43 carried upon the stationary needle-bar bushing 44 from which it is directed to the eye of the needle 9.

Referring particularly to Figs. 2 and 4, it is to be understood that the inner disk 33 and its pin 35 are driven in a counterclockwise direction while the outer disk 34 and its pin 36 are driven in a clockwise direction. Also, it will be observed that the outer disk 34 is provided with three apertures 45 which function to lighten the disk and at the same time provide access openings to the thread compartment between the disks 34 and 33 so as to permit broken thread and lint to be removed from the thread compartment.

Assuming the parts to be in the position shown in Fig. 6, the needle 9 has thrown out its thread loop and the beak 46 of the hook I 6 is just entering the needle loop. At this point in the cycle there is a small amount of slack in the thread 31 which lies over the thread-controlling elements 36 and :52.

In Fig. 7 the parts are shown at that point in the stitch-forming cycle just after the needle loop has been seized by the loop taker. It will be observed that the thread pin 35 has moved forward and downward in its orbit and is just about to release the thread while the pin 35 has moved in an opposite direction and into engagement with the thread so as to control the same as the pin 36 releases its control.

In Fig. 8 the parts are shown at that point in the stitch-forming cycle just prior to the time when the needle-loop is cast oif the loop taker beak. It will be observed from a comparison of Figs. 6 and 8 that, from the loop-seizing point to the cast-off point in the stitch-forming cycle, the thread-engaging element 36 has moved slightly more than one third of a revolution in a clockwise direction and the thread-engaging element 35 has moved a little more than of a revolution. By comparing Figs. 7 and 8 it will be appreciated that the thread-engaging elements 35 and 36 move from one position to the other at this portion of the cycle with each giving up thread to the hook. However, as the thread-engaging cycle changes from Fig. 7 to Fig. 8, the thread-engaging pin 35 and the hub 42 control the slack thread at all times. Again referring to Fig. 3, it will be observed that the pin 36 is moving upwardly so as to cause the thread to slip forward from the beak of the hook.

In Fig. 9 the stitch-setting point of the cycle is shown. When the mechanism moves from the position shown in Fig. 8 to that shown in Fig. 9, both of the thread-engaging elements 35 and 36 act conjointly to .pull upthe needle-loop and set the stitch. It will be noted that at the final stitch-setting point the thread-engaging elements 35 and 36 are acting conjointly to give a gentle stitch-setting pull on the thread. It will also be noted that during this stitch-setting portion of the cycle, the pin 35 is travelling in a clockwise direction and at the same time in a direction counter to the direction of thread lead, while the pin 35 is travelling in a counterclockwise direction and at the same time in a direction similar to that of the thread lead. It will also be understood that, although the movement of the pin 33 will set up a tension in the thread which will be added to the tension applied upon the thread by the tension device itself, the pin 33 is attempting to relieve this tension due to the fact that it is wiping across the thread in a direction similar to that of thread lead. Therefore, the movement of the pin 35 in a counterclockwise direction will compensate for the movement of the pin 3'6 in a clockwise direction insofar as the thread tension is concerned. Thus, it is to be understood that the combined frictional drag action of the pins 35 and 36 will result in no substantial increase or decrease in the tension imposed upon the thread by the tension unit 39. In other words, the frictional force set up by pin 36 is nullified by the counterfriction force set up by pin 35.

Fig. shows the position of the parts of the mechanism immediately after the needle-point has entered the work material for the succeeding stitch. In this view, it will be noted that the pin 35 is controlling the thread between the guide 4| and the pin 36, which thread would otherwise be slack due to the direction of rotation of the pin 36.

Considering now another feature of the present invention, it is to be noted that since the orbit of travel of the rotating pin 35 is contained within the orbit of travel of the pin 36, the abnormal winding of the thread about the pins is precluded in the event that the thread breaks. In other words, the pin 35 moves toward and away from the pin 36, and as the pin 35 has its orbit disposed within that of the pin 36, if the thread should break and begin to wind about the elements, the motion of the pin 35 toward and away from the other pin will break the needle thread and prevent it from winding about both of the elements.

Referring particularly to Figs. 11 and 12 there is illustrated a modified form of my invention in which a third rotary pin 41 is provided on the inner face of the disk 34 for the purpose of preventing the abnormal winding of the thread in the event that the latter should break. This pin 41 is spaced inwardly from the pin 36 and normally does not partake in any thread control action during the stitch-forming cycle. However, it is to be understood that the circular orbit of travel of the pin 35 on the inner disk 33 is so timed in relation to the pins 36 and 41 that it traces a complete loop about the pin 41 on the outer disk and in so doing passes bodily between the pins 36 and 41 of this outer disk as well as between the hub 42 and the innermost pin 41. It is apparent that this looping or crossing action of the respective pins serves to prevent abnormal winding of the needle-thread about any of the three thread-controlling pins in the event of thread breakage.

Still another feature of the present invention resides in the fact that with the orbits of travel of the take-up elements disposed one within the other, the take-up actuating shafts 21 and 28 are permitted to be disposed close together to the end that the design of the sewing machine head can be most compact. Such a design enhances both the efficiency of the machine as well as the appearance of the machine frame.

Havin thus set forth the nature of the invention, what I claim herein is:

1. A take-up for sewing machines comprising a frame, a pair of rotary take-up elements carried by said frame and operating substantially in the same plane with each element being rotatable about a respective one of a pair of parallel axes fixed within said frame and laterally spaced from each other a distance less than the combined radii of rotation of said two elements so that the orbit of travel of one of said elements has a portion thereof contained within the orbit of travel of the other of said elements, and mechanism for actuating said elements at uniform angular velocities.

2. A take-up for sewing machines comprising a frame, a pair of parallel overlapping rotary disks carried by said frame with each disk being rotatable about a respective one of a pair of parallel and laterally spaced axes fixed within said frame, said disks being spaced apart axially of each other thereby to form a thread-compartment therebetween, a pair of thread-engaging take-up elements of which each is carried upon a respective one of the opposing disk faces, the radii of said elements relative to their respective centers of rotation being such that their combined length is greater than the distance between their axes of rotation so that the orbit of travel of one element has a portion thereof contained Within that of the other element, and mechanism for actuating said disks at uniform angular velocities.

3. A take-up for sewing machines comprising a frame, a pair of rotary take-up elements operating substantially in the same plane and with each element being rotatable about a respective one of a pair of parallel axes fixed within said frame and laterally spaced from each other a distance less than the combined radii of rotation of said two elements so that the orbit of travel of one of said elements has a portion thereof contained within the orbit of travel of the other of said elements, and mechanism for actuating said elements at uniform angular velocities and in a timed relation so that one of said elements will trace a loop about the other of said elements.

4. A sewing machine having, in combination, a rotary needle-bar actuating shaft, a pair of rotary take-up shafts disposed in parallelism with said needle-bar actuating shaft, thread-engaging elements carried by said take-up shafts and operating on the same thread,'means for driving one of said take-up shafts directly from and at twice the angular velocity of said needle-bar actuating shaft, and means for driving the other of said take-up shafts directly from and at onehalf of the angular velocity of its associated takeup shaft.

5. A take-up for sewin machines comprising a frame, a plurality of rotary take-up elements carried by said frame and operating substantially in the same plane and with each element being rotatable about a respective one of a pair of parallel axes fixed within said frame and laterally spaced apart with the radius of rotation of a first of said elements being greater than the lateral distance between said two axes but less than the combined distance between said axes and the radius of rotation of a second element so that the orbit of travel of a first one of said elements will move to cross or intersect the orbit of travel of a second element, and mechanism for actuating said elements at uniform angular velocities.

6. A take-up for sewing machines comprising a frame, a plurality of rotary take-up elements carried by said frame and operating substantially in the same plane and with each element being rotatable about a respective one of a pair of parallel axes fixed within said frame and laterally spaced apart with the radius of rotation of a first of said elements being greater than the lateral distance between said two axes but less than the combined distance between said two axes and the radius. of rotation of a second element so that the orbit of travel of a first one of said elements will move to cross or intersect the orbit of travel of a second element, and mechanism for actuating said elements at uniform angular velocities and for rotating said first element in a direction opposite to that of said second element.

7. A take-up for sewing machines comprising a frame, a pair of parallel overlapping rotary disks carried by said frame with each disk being rotatable about a respective one of a pair of parallel and laterally spaced axes fixed within said frame, said disks being spaced apart axially of each other thereby to form a thread compartment therebetween, a pair of thread-engaging elements of which each is carried upon a respective one of the opposing disk faces with the radius of rotation of a first of said elements being greater than the lateral distance between said two axes but less than the combined distance between said axes and the radius of rotation of a second element so that the orbit of travel of one element crosses or intersects that of the other element, and mechanisms for actuating said disks at uniform angular velocities.

8. A take-up for sewing machines comprising a plurality of rotary take-up elements operating substantially in the same plane, two of suchelements being rotatable about a fixed axis and a third element being rotatable about a second fixed axis laterally spaced from the other axis, the orbit of travel of said elements being such that the third element passes between the first two elements, and mechanism for actuating said elements at uniform angular velocities.

9. A take-up for sewing machines comprising a pair of parallel overlapping rotary disks of which each is rotatable about a respective one of a pair of fixed and laterally spaced axes, said disks being spaced apart axially of each other thereby to form a thread compartment therebetween, thread-engaging elements carried upon the respective opposing disk faces, the radii of said elements relative to their respective centers of rotation being such that one element of one disk passes between two elements of the other disk, and mechanism for actuating said disks at uniform angular velocities.

10. A sewing machine having, in combination, a frame, a pair of laterally spaced parallel shafts each being journaled within said frame for rotation about a fixed axis, a pair of thread-engaging elements of which each is carried upon a respective one of said shafts, the radii of said elements relative to their respective centers of rotation being such that the orbit of travel of one element has a portion thereof contained within that of the other element, and mechanism connected with said shafts for rotating them at uniform angular velocities.

11. A take-up for sewing machines comprising a pair of overlapping rotary disks of which each is rotatable about a respective one of a pair of fixed and laterally spaced axes, said disks being spaced apart axially of each other thereby to form a thread-compartment therebetween, a central hub-like thread-engaging element disposed coaxially of-and secured to the hub portion of one of said-disks so as to bridge completely the thread-compartment, a pair of thread-engaging take-up elements of which each is carried upon a respective one of the opposing disk faces, the radii of said latter two elements relative to their respective centers of rotation being such that the orbit of travel of one element has a portion thereof contained within that of the other element, and mechanism for actuating said disks at uniform angular velocities.

12. A sewing machine having, in combination, a frame, a pair of laterally spaced parallel shafts each being journaled within said frame for rotation about a fixed axis, a pair of overlapping rotary disks of which each is secured at its hub portion directly upon and coaxially of a respective one of said shafts, said disks being spaced apart axially of each other thereby to form a threadcompartment therebetween which is bridged by an end portion of one of said shafts, a pair of threadengaging take-up elements of which each is carried upon a respective one of the opposing diskfaces, the radii of said latter two elements relative to their respective centers of rotation being such that the orbit of travel of one element has a portion thereof contained within that of the other element, and mechanism for actuating said shafts at uniform angular velocities.

13. A sewing machine having in combination, a frame, a pair of laterally spaced parallel shafts each being journaled within said frame for rotation about a fixed axis, means for rotating said shafts with one of said shafts having twice the angular velocity as the other, a pair of overlapping rotary disks of which each is secured at its hub portion directly upon and coaxially of a respective one of said shafts, said disks being spaced apart axially of each other thereby to form a thread-compartment therebetween which is bridged by an end portion of one of said shafts, and a pair of thread-engaging take-up elements of which each is carried upon a respective one of the opposing disk faces, the radii of said latter two elements relative to their respective centers of rotation being such that the orbit of travel of one element is completely disposed within that of the other element References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,314,513 Parry Mar. 23, 1943 2,332,087 'Karle Oct. 19, 1943 

